Stent with cover connectors

ABSTRACT

A stent suitable for maintaining the patency of a bodily lumen, generally comprising a tubular body configured to facilitate connection of a cover thereto. A stent assembly of the invention generally comprises a stent having cover connectors in contact with a cover to secure the cover to a surface of the stent. The invention also comprises methods of securing a cover to a stent. In a first embodiment, the cover connector on an expandable tubular body has a first section, a second section, and a third section between the first and second sections. The connector has an open configuration, and a closed configuration in which the first section has at least one bend and the second section has at least one bend, so that the first and second sections are bent together and are directed towards the third section therebetween. In a second embodiment, a cover connector is secured to an end of the expandable tubular body, and is configured to fold from an open configuration to a closed configuration in which the connector extends toward a midpoint of the tubular body between the first and second ends of the tubular body and contacts a cover located between the cover connector and a surface of the stent, to secure the cover thereto.

STENT WITH COVER CONNECTORS

[0001] This application is a continuation-in-part application of U.S.patent application Ser. No. 09/522,336, entitled STENT WITH COVERCONNECTORS, filed Mar. 9, 2000, incorporated herein in its entirety byreference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to the field of intraluminal supportdevices such as stents and the like. Typically, stents are expandable,tubular metallic devices that are positioned within a patient'svasculature or other body lumen and expanded in order to support avessel or body lumen at a desired intraluminal location to allow theflow of blood or other body fluids therethrough. Often, the stents areformed from a deformable metal and delivered to the desired intraluminallocation by mounting the stent onto an expandable portion, e.g. aballoon, on the distal extremity of a delivery catheter. By advancingthe catheter through the body lumen, the stent may be delivered to adesired position and expanded therein by expanding the balloon to anexpanded configuration, seating it within the artery or other bodylumen. Other implementations make use of a self-expanding stent formedfrom a suitable material such as pseudoelastic material that isdelivered in a constricted condition and when released spontaneouslyexpands to an enlarged configuration. A stent made of superelastic alloy(e.g. NiTi alloy) may be inserted into the body lumen with a stressinduced martensitic phase and expanded within the body lumen. Furtherdetails of stents and stent delivery systems may be found in U.S. Pat.No. 5,507,768 (Lau et al.), U.S. Pat. No. 5,458,615 (Klemm et al.), andU.S. Pat. No. 5,514,154 (Lau et al.), incorporated herein by referencein their entireties.

[0003] Stents are often used in conjunction with an intravasculartreatment for conditions such as obstructive coronary artery disease andperipheral artery disease. For example, ablation, atherectomy, balloondilation, laser treatment or other procedures are among the methods usedto widen a stenotic region of a patient's vasculature. However,restenosis occurs in large percentage of percutaneous transluminalcoronary angioplasty (PTCA) patients and rates can be even higher withother procedures. Restenosis is thought to be a natural healing reactionprovoked by injury from the intravascular procedure. The healing processfrequently causes thrombosis and may lead to intimal hyperplasia thatoccludes the vessel. The prior art has employed a number of mechanicaland pharmacological strategies to reduce the restenosis rate, but nonehave been particularly effective. Accordingly, stents have been proposedto maintain the patency of a treated vessel and reduce restenosis. Usingstents, restenosis rates have fallen to less than 20%. Although helpfulin reducing restenosis, stents do not represent a complete solution. Theframework of the stent may still allow migration and proliferation ofthe smooth muscle cells, while the stent itself can be thrombogenic. Toaddress these problems, stents have been provided with covers made fromvarious materials such as DACRON, polytetrafluoroethylene (PTFE),heterologous tissue and autologous veins, arteries and tissue.

[0004] It would be a significant advance to provide a stent with animproved connector for securing a cover to the stent. This inventionsatisfies these and other needs.

SUMMARY OF THE INVENTION

[0005] The invention is directed to a stent suitable for maintaining thepatency of a bodily lumen, generally comprising a tubular bodyconfigured to facilitate connection of a cover thereto. A stent assemblyof the invention generally comprises a stent having at least one coverconnector on the tubular body in contact with a cover to secure thecover to a surface of the stent. The invention also comprises methods ofsecuring a cover to a stent.

[0006] In a first embodiment, the cover connector on an expandabletubular body has a first section, a second section, and a third sectionbetween the first and second sections. The connector has an openconfiguration, and a closed configuration in which the first section hasat least one bend and the second section has at least one bend, so thatthe first and second sections are bent together and are directed towardsthe third section therebetween. The ends of the connector are configuredto pierce the cover so that at least a portion of the first and secondsections extend through the cover. With the cover pierced by the firstand second ends of the connector, the ends of the connector are benttogether towards the third section, so that the first and secondsections of the connector are adjacent an outer surface of the cover andthe third section of the connector is adjacent an inner surface of thecover, to form the closed configuration. A stent assembly of theinvention generally comprises a covered stent having at least a portionof the first and second sections of the cover connector extendingthrough a cover, to secure the cover to the stent. In one embodiment thecover connector is configured to draw the lengthwise edges of a stentcover together as the connector is bent from the first to the secondconfiguration to close the cover about the stent surface.

[0007] A method of securing a cover to a stent generally comprisespiercing the first end of the cover connector at a first location on thecover and piercing the second end of the cover connector through thecover at a second location from an inner surface to an outer surface ofthe cover. The first and second sections of the cover connector are benttowards the third section to form the closed configuration and securethe cover to the stent.

[0008] In a second embodiment, the cover connector presses the coveragainst a surface of the stent to secure the cover thereto withoutpiercing the cover. The cover connector is secured to an end of theexpandable tubular body of the stent, and is configured to fold from anopen configuration to a closed configuration in which the connectorextends toward a midpoint of the tubular body between the first andsecond ends of the tubular body and contacts a cover located between thecover connector and a surface of the tubular body of the stent, tosecure the cover thereto. The cover connector presses the cover againsta surface of the stent to secure the cover thereto without piercing thecover. A method of securing a cover to a stent generally comprisesplacing a cover on the stent and folding the cover connector from theopen configuration to the closed configuration so that at least asection of the cover is in contact with the cover connector and betweenthe cover connector and a surface of the stent.

[0009] The cover connectors may be configured to secure a cover toeither an inner surface or an outer surface of the tubular body of thestent. In a presently preferred embodiment, a plurality of coverconnectors are provided on the stent to connect a cover which extendsover a substantial portion, and preferably all of the length of thestent, in order to minimize restenosis in the body lumen.

[0010] In one embodiment, a stent is provided with eyelet members havingan opening therein configured to receive a securing member such as asuture to thereby secure a cover to the stent.

[0011] The cover may be a variety of suitable materials which arepreferably expandable, biocompatible, and non-thrombogenic, includingautologous tissue, heterologous tissue such as bovine pericardium,porcine pericardium, aortic leaflet, and polymeric materials such asPTFE and polyesters such as DACRON. In a preferred embodiment, the coveris generally cylindrical for corresponding to the tubular framework orthe stent.

[0012] The stent may be an expandable, tubular framework and may be aconventional self expanding or balloon expandable stent. A variety ofstent designs may be used, including stents formed from braided tube,slotted tubes, and coils or closed sinusoidal rings of wire or ribbon,and the like.

[0013] Another embodiment of the invention comprises a stent having anexpandable tubular body having a first end, a second end, a plurality ofcylindrical wall sections defining an open-walled structure, and havinga plurality of bar members connected to the tubular body. Each barmember is connected to and extends between longitudinally adjacentcylindrical wall sections. In one embodiment, at least one bar member isbetween longitudinally adjacent cylindrical wall sections. In oneembodiment, the stent is part of a stent assembly including a coverhaving a first end, a second end, and an intermediate section betweenthe first and second ends. The cover is disposed over at least onesection of the stent and under at least a second section of the stent.For example, in one embodiment, an intermediate section of the cover isadjacent to an outer surface of the intermediate wall section of thestent, and the first end and the second end of the cover are adjacent toan inner surface of the cylindrical wall sections at the first andsecond ends, respectively, of the stent. In an alternative embodiment,the intermediate section of the cover is adjacent to an inner surface ofthe intermediate cylindrical wall section of the stent, and the firstend and the second end of the cover are adjacent to an outer surface ofthe cylindrical wall sections at the ends of the stent. The cover isdisposed between a portion of a cylindrical wall section and a barmember connecting the cylindrical wall section to a longitudinallyadjacent cylindrical wall section of the tubular body. Consequently, thestent facilitates attaching the cover to the stent, and the stentassembly having a cover on the stent provides a securely attached cover,and avoids or reduces disadvantageous damage to the cover duringattachment. Disposing a section of the ends of the cover between aportion of the stent tubular body and the bar member attached to thatportion in accordance with the invention prevents or inhibitsdisplacement of the cover relative to the stent during advancement ordeployment of the stent assembly within a patient's body lumen. Thecylindrical wall sections of the stent are thus configured as coverconnectors in that the ends of the cover can be disposed between thewall section and the bar members attached thereto, and can be disposedunder some wall sections while being disposed over other wall sections,to secure the cover to the stent. In a presently preferred embodiment,the cover is further secured to the stent with securing members such assuture, clips, wires, and the like. In one embodiment the stent has atleast one eyelet member with an opening configured to receive a securingmember therein to secure a cover to the tubular body.

[0014] The stent assembly is implanted in the patient's body lumen,typically by mounting the stent assembly on the distal extremity of adelivery catheter. Specifically, a tubular stent with a cover disposedabout at least part of the stent, and secured thereto by the coverconnectors, is mounted on a balloon, for a balloon expandable stent, oron a containing mechanism for a self expandable stent. The catheter isadvanced through the body lumen within the patient until the distalextremity of the catheter having the stent assembly is positioned at adesired location therein. The stent assembly is expanded by expandingthe balloon or releasing the containing mechanism on which the stentassembly is mounted to anchor the stent assembly within the body lumen.Once the stent assembly is effectively positioned within the body lumen,the expanded balloon may be contracted, e.g. by deflation, and then thedelivery catheter may be withdrawn.

[0015] The stent having cover connectors of the invention provides foreasy attachment of a stent cover onto the stent. This is particularlyadvantageous in the case of a cover which is impregnated with atherapeutic or diagnostic agent, such as an angiogenesis orantithrombotic agent, just before use or stored in the agent topreimpregnate the cover. The cover connectors allow the impregnatedcover to be quickly and easily attached to the stent just beforeimplantation of the stent assembly in the patient's body lumen.Thereafter, the stent assembly can be positioned at a desired sitewithin the patient's body lumen, where the cover will release thetherapeutic agent.

[0016] The cover connectors of the invention provide for improvedconnection of a cover to a stent surface, by providing an easily formedconnection between the cover and the stent. The cover connectors of theinvention avoid the use of sutures or adhesive to secure the cover tothe stent, yet provide a durable, rugged, low profile connection. Theseand other advantages of the invention will become more apparent from thefollowing detailed description and exemplary figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is an elevational view of a stent having cover connectorswhich embodies features of the invention.

[0018]FIG. 2 is an enlarged view of the stent shown in FIG. 1,illustrating the cover connector in an open configuration.

[0019]FIG. 3 illustrates the cover connector shown in FIG. 2, in a bentU-shaped configuration.

[0020]FIG. 4 is a perspective view, partially in phantom, of a stentassembly which embodies features of the invention illustrating a coversecured to the stent.

[0021]FIG. 5 is a transverse cross sectional view of the stent assemblyshown in FIG. 4, taken along lines 5-5.

[0022]FIG. 6 is a perspective view, of an alternative embodiment of astent assembly which embodies features of the invention, in which thecover connector is axially aligned in the open configuration with thelongitudinal axis of the stent

[0023]FIG. 7 is longitudinal cross sectional view of a section of thestent assembly shown in FIG. 6, taken along lines 7-7.

[0024]FIG. 8 is an elevational view, partially broken away and partiallyin section, of an alternative embodiment of a stent assembly whichembodies features of the invention, having cover connectors in an openconfiguration on the ends of the stent.

[0025]FIG. 9 is an elevational view of the stent assembly shown in FIG.8, illustrating the cover connectors in a closed configuration.

[0026]FIG. 10 is a longitudinal cross sectional view of the stentassembly shown in FIG. 9, taken along lines 10-10.

[0027]FIG. 11 is an elevational view, partially in longitudinal crosssection, of a stent assembly which embodies features of the invention,having eyelet members comprising a body having eyelets in opposite endsof the body, the body being attached to a support member, and havingsutures in the eyelet members connecting the cover to the stent.

[0028]FIG. 12 is an elevational view, partially in longitudinal crosssection, of an alternative embodiment of a stent assembly which embodiesfeatures of the invention having eyelet members attached to a supportmember, and having sutures in the eyelet members connecting the cover tothe stent.

[0029]FIG. 13 is a transverse cross sectional view of the eyelet membersshown in FIG. 11, taken along line 13-13.

[0030]FIG. 14 is an elevational view of a stent having eyelet memberscomprising closed rings or loops attached to the stent, which embodiesfeatures of the invention.

[0031]FIG. 15 is an elevational view of a stent having eyelet memberscomprising open rings or lopes attached to the stent, which embodiesfeatures of the invention.

[0032]FIG. 16 is a perspective view, partially in phantom, of a stentassembly which embodies features of the invention, illustrating a coversecured to the stent by sutures in eyelet members attached to the stent.

[0033]FIG. 17 is an elevational view of an alternative embodiment of astent which embodies features of the invention.

[0034]FIG. 18 is an elevational view of the stent shown in FIG. 17having a cover on the stent.

[0035]FIG. 19 is fragmentary sectional view of the stent and coverassembly shown in FIG. 18.

[0036]FIG. 20 is a transverse cross sectional view of the stent andcover assembly shown in FIG. 18, taken along line 20-20.

[0037]FIG. 21 is an elevational partial view, partially in phantom, ofan alternative embodiment which embodies features of the invention,having a cover extending beyond a first end of the stent.

[0038]FIG. 22 is an elevational partial view, partially in phantom, ofthe covered stent shown in FIG. 21, having the edges of the extended endof the cover joined together.

[0039]FIG. 23 is a transverse view of the covered stent shown in FIG. 22taken along line 23-23.

DETAILED DESCRIPTION OF THE INVENTION

[0040]FIG. 1 is an elevational view of a first embodiment of a stent 10which embodies features of the invention, comprising an expandabletubular body 11 having first and second ends, a lumen therein, and aframework of spaced apart wall sections 12 defining an open-walledstructure, and cover connectors 13 on the tubular body. The coverconnectors 13, which are illustrated in more detail in FIG. 2, showingan enlarged view of the connectors shown in FIG. 1, have a first end 15,a second end 16, a first section 17 adjacent to the first end 15, asecond section 18 adjacent to the second end 16, and a third section 21between the first and second sections. The connector 13 is illustratedin FIG. 2 in an open configuration in which the connector is a generallystraight, pointed projection attached to the tubular body. FIG. 3illustrates the connector shown in FIG. 2 bent into a generally U-shapedconfiguration which facilitates piercing the ends of the connectorthrough a cover to be secured to the stent. The connector is bent at afirst location (forming bend 23) on the first section so that at least asection of the first section is above the tubular body, and at a firstlocation (forming bend 25) on the second section so that at least asection of the second section is above the tubular body. FIG. 4illustrates a cover 22 pierced by the ends of the cover connector. Asbest illustrated in FIG. 5, showing a transverse cross section of thestent assembly shown in FIG. 4, taken along lines 5-5, the coverconnector assumes the closed configuration as the first section 17 andthe second section 18 are bent so that at least a portion of the firstand second sections are in contact with the outer surface of the coverand the third section 21 is adjacent the inner surface of the cover. Inthe presently preferred embodiment illustrated in FIG. 5, the coverconnector assumes the closed configuration when the first section has afirst bend 23 and a second bend 24 in the same direction as the firstbend in the first section, and the second section has a first bend 25and a second bend 26 in the same direction as the first bend in thesecond section. However, the closed configuration can be formed by asingle bend in the first section and a single bend in the second sectionwhen the angle of the bend is large enough that the first and secondsections contact the outer surface of the cover (not shown).

[0041] In the embodiment illustrated in FIG. 5, the second bend 24 onthe first section is between the first end 15 of the connector and thefirst bend 23 on the first section, and the second bend 26 on the secondsection is between the second end 16 of the connector and the first bend25 on the second section. In an alternative embodiment in which theconnector is configured to draw the edges of the cover together as theconnector is bent into the closed configuration, the second bend 24 onthe first section is between the third section 21 of the connector andthe first bend 23 on the first section, and the second bend 26 on thesecond section is between the third section 21 of the connector and thefirst bend 25 on the second section. Thus, with the connector in theU-shaped configuration illustrated in phantom in FIG. 5 and the coverpierced by the first and second ends of the connector, as the connectoris bent at the second location on the first and second sections to formthe second bend 24, the cover will be stretched about the stent and theedges of the cover pushed together or further around the stent.Similarly, in the embodiment illustrated in FIG. 5, a portion 27 of thefirst section between the first and second bends thereon is directedperpendicular to the third section, and a portion 28 of the secondsection between the first and second bends thereon is directedperpendicular to the third section. In an alternative embodiment (notshown), after the cover 22 is placed on the connector, the portion 27between the first and second bends on the first section and the portion28 between the first and second bends on the second section are disposedat an angle toward the third section 21 by further bending the firstbends 23 and 25 from a perpendicular angle to an acute angle, so thatthe edges of the cover are pushed or drawn together.

[0042] In FIG. 4, a first cover connector 13 a is in the closedconfiguration, and cover connectors 13 b and 13 c are in the U-shapedconfiguration. FIG. 4 illustrates the cover 22 in phantom before beingwrapped around the stent and connected thereto by the cover connectors13. The cover 22 is in the form of a sheet of material wrapped aroundthe stent, with a first end 31 and a second end 32, and first 33 andsecond 34 edges extending the length of the cover from the first to thesecond end thereof. In the presently preferred embodiment illustrated inFIG. 5, the two edges 33/34 of the cover corresponding to the length ofthe cover are abutting. However, in an alternative embodiment the edgesmay overlap one another as illustrated in FIGS. 6 and 7. Additionally,although the cover is illustrated as a sheet of material wrapped aroundthe stent, the cover could be preformed into a tubular cylinder beforebeing placed on the stent and connected thereto.

[0043] In one embodiment, the connector is optionally provided withweakened sections configured to bend, as for example by thinning ornarrowing the connector at the locations configured to bend. Theconnector 13 has a length that is typically about 0.15 mm to about 10mm, preferably about 0.5 mm to about 4 mm, and a width that is about0.07 mm to about 2 mm, preferably about 0.1 mm to about 1 mm. The firstand second sections have a length of about 0.1 to about 6 mm, preferablyabout 0.33 to about 2.6 mm. The third section has a length of about 0.05to about 4 mm, preferably about 0.17 to about 1.4 mm.

[0044] The cover connectors may be secured to the tubular body in avariety of configurations. In the presently preferred embodiment of theinvention shown in FIG. 1, the cover connector 13 is attached to asupport member 35 extending between the spaced apart wall sections ofthe tubular body of the stent. The support member has a first endsecured to the tubular body and a second end secured to the tubularbody, and the third section of the connector is secured to the supportmember between the first and second ends of the support member. Thecover connectors may be manufactured as a separate part and later joinedto the tubular body, or manufactured with the tubular body as a onepiece unit. The terms “secured” and “attached” as used herein to discussthe connection between the cover connectors and the tubular body shouldbe understood to include cover connectors separately joined to thetubular body and cover connectors made as a section of the tubular body.

[0045] In a presently preferred embodiment, the connector has alongitudinal axis which is not axially aligned with the tubular bodylongitudinal axis. As a result, the connector can be used to secure thetwo edges 33/34 of the cover without the need for preattaching the edges33/34 of the cover together to form a cylinder, or without overlappingthe edges of the cover. In the presently preferred embodimentillustrated in FIG. 1, the cover connector is substantiallyperpendicular to the longitudinal axis of the tubular body of the stentin the open configuration. By substantially perpendicular, it should beunderstood that the angle the cover connector makes relative to thelongitudinal axis may be 90° or somewhat different from a 90° angle, asfor example by about 65° to about 115°. However, in an alternativeembodiment, the cover connector may have a longitudinal axis axiallyaligned with the tubular body longitudinal axis. FIGS. 6 and illustratea cover connector which is directed substantially parallel to thelongitudinal axis of the tubular body in the open configuration. Asillustrated in FIG. 6 showing the stent with a cover being securedthereto, and FIG. 7 showing a cross section of the assembly shown inFIG. 6 taken along lines 7-7, the edges of the cover 22 are overlappingso that sections of cover adjacent to the opposite edges of the stentcan be pierced by the first and second ends of the connector to securethe cover to the stent.

[0046]FIG. 8 illustrates an alternative embodiment of a stent 40embodying features of the invention, comprising an expandable tubularbody having a first end 41, a second end 42, and a midpoint 43therebetween, and a framework of spaced apart wall sections 44 definingan open-walled structure. The stent 40 has at least one cover connector45 secured to an end of the tubular body. The cover connector 45 has anopen configuration, and a closed configuration in which the connectorextends toward the midpoint of the tubular body, and is configured tofold from the open configuration to the closed configuration to contacta cover 22 located between the cover connector and a surface of thestent. In the embodiment illustrated in FIG. 8, the stent has aplurality of cover connectors secured about a circumference of the firstend and the second end of the tubular body of the stent. FIG. 9illustrates the cover connectors 45 in the closed configuration in whichthe cover connector is folded so that at least a section of the cover 22is between the cover connector and the outer surface of the stent withan outer surface of the cover 22 in contact with the cover connector. Asbest illustrated in FIG. 10 showing a longitudinal cross section of theassembly shown in FIG. 9 taken along lines 10-10, the connectors 45 arefolded in the closed configuration so that they have a surface which issubstantially parallel to a surface of the tubular body for maximumcontact with the cover. By substantially parallel, it should beunderstood that the surface of the cover connectors 45 adjacent to thecover is completely or nearly completely in contact with the cover. Asillustrated in FIG. 10, the edges 33/34 of the cover 22 extending thelength of the cover are overlapping. However, in an alternativeembodiment (not shown), the edges of the cover are abutting. In thisembodiment, one cover connector 45 preferably contacts both edges of thecover to hold the two edges securely together. One or more of the coverconnectors 13 may be provided on stent 40, together with coverconnectors 45. In one embodiment, the cover connectors 13 are providedon the ends of stent 40 together with cover connectors 45.

[0047] In the embodiment illustrated in FIG. 8, the connector 45 is aloop, and is formed by a wire or ribbon, which provides for optimalsurface contact between the cover and the cover connector withoutforming a disadvantageous barrier between the cover and the vessel wallin which the stent assembly will be implanted. However, it would beobvious that a variety of other suitable shapes may be used includingdiscs, fingers or projections, and the like. The cover connector 45 hasa length that is typically about 0.5 mm to about 10 mm, preferably about1 mm to about 4 mm, and a width that is about 0.07 mm to about 2 mm,preferably about 0.1 mm to about 2 mm. The width of the wire or ribbonforming the connector in FIG. 8 is about 0.1 mm to about 1 mm.

[0048]FIG. 11 illustrates an alternative embodiment of a stent assembly50 which embodies features of the invention, having eyelet members 51comprising an elongated body 52 having one or more eyelets or openings53 in opposite ends of the body 52. The body 52 is attached to a supportmember 54 which extends across adjacent coiled sections of stent 55. Theopenings 53 are configured to receive a securing member, to therebyconnect cover 22 to stent 55. A variety of suitable securing members maybe used including sutures, staples, hooks, and wires. In the embodimentillustrated in FIG. 11, sutures 56 are in the openings 53 to connect thecover to the stent. FIG. 13 is a transverse cross sectional view of theeyelet member 51 shown in FIG. 11, taken along line 13-13, illustratinga suture 56 in each opening 53 with knotted ends to connect cover 22 tostent 55.

[0049] In an alternative embodiment of a stent assembly which embodiesfeatures of the invention, illustrated in FIG. 12, eyelet members 57attached to support member 54 comprise openings 58 on either side of thesupport member 54, so that each opening 58 is directly adjacent to thesupport member 54. Sutures 56 in each opening 58 connect the cover 22 tothe stent 55.

[0050]FIG. 14 illustrates an alternative embodiment of a stent 55 havingeyelet members 59 comprising closed rings or loops attached to thestent, which embodies features of the invention. The eyelet members 59extend from the side of the stent 55 on the ends of the sinusoidal turnsof the stent, with a central opening 60 configured to receive suture 56or other securing member, to connect the cover 22 to the stent 55. In analternative embodiment, eyelet members 61 are open rings or loops, asfor example with an aperture 62 adjacent to the edge of the turns of thestent 55 and with an opening 63 configured to receive suture 56 or othersecuring member, illustrated in FIG. 15. In the embodiment of FIGS. 14and 15, eyelet members 59 and 61 are on the top outer edge of adjacentsinusoidal turns of the stent 55. However, in alternative embodimentsthe eyelet members may be provided on nonadjacent turns of the stent 55as for example on alternate turns.

[0051] In a presently preferred embodiment, eyelet members 51/57/59/61are around the circumference of the stent 55. However, in alternativeembodiment, eyelet members may be only along a narrow section of thestent 55 along the length of the stent 55, as illustrated in FIGS. 14and 15, as for example, where a seam of the tubular cover 22 is located.FIG. 16 illustrates a perspective view, partially in phantom, of a stentassembly which embodies features of the invention, illustrating a cover22 secured to the stent 55 by sutures 56 in eyelet members 59 attachedto the stent 55. A variety of suitable materials may be used to form theeyelet members including stainless steel, nitinol, and tantalum. In apresently preferred embodiment, the eyelet members are formed of thesame material as stent 55. The eyelet members may be formed integralwith the stent, or alternatively as a separate member secured thereto,as for example by welding. Preferably, the eyelet members have the samethickness as the stent 55.

[0052] The cover 22 is preferably a biocompatible, non-thrombogenicmaterial, such as tissue, PTFE, or DACRON. The thickness of the cover istypically from about 0.07 mm to about 1 mm, and preferably is about 0.1mm to about 0.4 mm. The cover 22 preferably has a length configured tocover the length of the expanded stent, as illustrated in FIG. 4,showing a stent with a cover 22 extending the length of the stent, witha length equal to the stent length. However, the cover may have a lengththat is less than or greater than the length of the stent. The coverpreferably has a circumference about equal to the circumference of theexpanded stent, configured to fit on an inner or outer surface of theexpanded stent. The cover preferably fits on the expanded stent so thatthe cover conforms to the expanded stent without flaps of excessmaterial. The cover may be provided on the unexpanded stent in a foldedor overlapping wrapped configuration which provides sufficient materialwhich will unwrap or stretch to cover the larger circumference of theexpanded stent.

[0053] The cover connectors 13/45 are preferably formed of a metallicmaterial such as stainless steel. However, other resilient materialswhich are flexible enough to be bendable but stiff enough to hold thebent shape of the closed configuration can be used including platinum ornickel-titanium alloy such as nitinol. Additionally, at least a portionof first section 17 and second section 18 of cover connector 13 may besecured together, as for example by spot welding, after being bent intothe closed configuration to secure the cover to the tubular body of thestent.

[0054] Stent is typically a metallic material and may comprise a varietyof suitable stent designs. For example, in the embodiment where thecover connector is a separate part joined to a stent, a variety ofcommercially available stents may be used such as Micro Stent II and GFXstents available from Arterial Vascular Engineering, and Multi-Link,available from Guidant. Other stents that may be used in the practice ofthis invention include the Palmaz-Shatz stent from Johnson and Johnson,the Gianturco stent from Cook Incorporated and other commerciallyavailable stents. Conventional balloon expandable stents are preferred,but self-expanding stents, such as those formed from shape memorymaterials, are also suitable. The length of the stent, for coronaryapplications, is generally about 4 to greater than about 80 mm,typically about 5 to about 80 mm, preferably about 10 to about 50 mm.The stent generally has a diameter of about 1.5 to about 35 mm,typically about 2 to about 6 mm, preferably about 2.5 to about 5 mm. Theactual length and diameter of the stent and cover may vary, and willdepend on the nature of the vessel in which the stent assembly isimplanted. For example, for peripheral vessel applications, such as anaortic abdominal aneurysm, a larger stent having a length of about 5 mmto about 200 mm and a diameter of about 2 mm to about 60 mm would beused.

[0055] An alternative embodiment of the invention is illustrated in FIG.17. FIG. 17 illustrates a stent 70 generally comprising an expandabletubular body 71 having a first end 72, a second end 73, a plurality ofcylindrical wall sections 74 defining an open-walled structure. The wallsections 74 are longitudinally spaced apart from one another so thateach individual wall section 74 is longitudinally adjacent to at leastone other wall section 74. The tubular body 71 has eyelet members 75formed by the turns of the wall section 74. A plurality of bar members76 are connected to the tubular body 71. As illustrated in FIG. 17,longitudinally adjacent wall sections 74 have at least one bar member 76connected to and extending therebetween. In a presently preferredembodiment, at least two bar members 76 are connected to and extendbetween longitudinally adjacent wall sections 74. The bar member 76provides support to and connects the wall sections 74, and in theillustrated embodiment comprises a solid member having a circular crosssection. However, the bar member can have a variety of suitableconfigurations including hollow or tubular, and with circular, oblong,square, or rectangular cross sections.

[0056] In the embodiment illustrated in FIG. 17, each wall section 74comprises a curvilinear member Which extends around a circumference ofthe tubular body 71 and which has a plurality of turns 78, each turnhaving a concave surface 81 facing in a direction opposite to theconcave surface 81 of a radially adjacent turn 78 on the same wallsection as the turn, and a convex surface 82 facing in a directionopposite to the convex surface 82 of a radially adjacent turn 78 on thesame wall section as the turn. The juncture between radially adjacentturns on a wall section 74 is at the longitudinal midpoint along thelength of the wall section 74. Each bar member 76 is connected to andextends between the concave surface 81 of a turn 78 and the convexsurface 82 of a turn 78 on a longitudinally adjacent wall section. Inthe embodiment of FIG. 17, the turns 78 of an individual wall section 74are in phase with the turns of a longitudinally adjacent wall section74. The terminology “in phase” should be understood to mean that theturns 78 are lined up along the length of the stent, with turns 78 on awall section 74 facing in the same direction as the turns in linetherewith on the longitudinally adjacent wall section 74. In contrast,in the embodiment illustrated in FIG. 1, the turns of a wall section 12are out of phase with the turns on the adjacent wall section 12. In apresently preferred embodiment of the stent illustrated in FIG. 17, theturns 78 are in phase with the turns 78 of the adjacent wall section 74.As a result, the manufacture of the stent 70 is facilitated, and thelength of the bar member 76 is relatively short and provides arelatively strong connection between adjacent wall sections 74 ascompared to a bar member connecting turns 78 which are out of phase.However, in an alternative embodiment of stent 70, the turns 78 oflongitudinally adjacent wall sections 74 are out of phase with oneanother (not shown), wherein each bar member 76 is connected to andextends between the concave surface 81 of a turn 78 and the concavesurface 81 of a turn 78 on a longitudinally adjacent wall section 74.

[0057] The stent 70 has a first wall section 83 at the first end of thetubular body, a second wall section 84 at the second end of the tubularbody, and intermediate wall sections 85 located between the first andsecond wall sections 83/84. The turns 78 of the first wall section 83which have convex surfaces 82 which face toward the intermediate wallsections 85 are not connected to a bar member 76, i.e., the convexsurfaces of the turns closest to the adjacent intermediate wall section85 are not directly connected by a bar member or other member to theadjacent intermediate wall section 85. Consequently, a first section ofa cover can be disposed on a surface of the intermediate wall sections85 with a second section of the cover disposed on an opposite surface ofthe first and/or second wall section 83/84. More specifically, the endsof a cover can be placed under the first and second wall sections 83/84while the intermediate section of the cover is over the intermediatesection of the stent.

[0058]FIG. 18 illustrates the stent 70 shown in FIG. 17 with a cover 90on the stent 70. The cover has a first end 91, a second end 92 and anintermediate section 93 between the first and second ends 91/92. As bestillustrated in FIG. 19, showing a fragmentary sectional view of coveredstent at the first end 72 of the stent, with the cover 90 partiallybroken away, the first end 91 of the cover is adjacent to an innersurface of the first wall section 83. Similarly the second end 92 of thecover is adjacent to an inner surface of the second wall section 84.Conversely, the intermediate section 93 of the cover is adjacent to anouter surface of the intermediate sections 85. In an alternativeembodiment, the intermediate section 93 is adjacent an inner surface ofthe intermediate sections 85, and the first and second ends 91/92 of thecover are adjacent an outer surface of the first and second wallsections 83/84 (not shown). While discussed primarily in terms of havingboth the first and the second end 91/92 of the cover 90 on an oppositesurface from the cover intermediate section 93, it should be understoodthat only one end of the cover may be so disposed with the opposite endon the same surface of the stent 70 as the intermediate section 93 ofthe cover 90.

[0059] The inner surface of the first end 91 of the cover is adjacent toan outer surface of the bar members 76 which extend between the firstwall section 83 and the intermediate wall section 85 longitudinallyadjacent thereto. Similarly, the inner surface of the second end 92 ofthe cover is adjacent to an outer surface of the bar members 76 whichextend between the second wall section 84 and the intermediate wallsection 85 longitudinally adjacent thereto. Consequently, the first end91 of the cover 90 is disposed between the first wall section 83 and thebar members 76 secured thereto, and the second end 92 of the cover 90 isdisposed between the second wall section 84 and the bar members 76secured thereto. In a presently preferred embodiment, at least one barmember 76, and most preferably two bar members 76, are connected to andextend between the first wall section 83 and the intermediate wallsection 85 longitudinally adjacent thereto, and at least one bar member76, and most preferably two bar members 76, are connected to and extendbetween the second wall section 84 and the intermediate wall section 85longitudinally adjacent thereto. However, any number of bar members 76can be provided as are desired for providing sufficient stability to thetubular body of the stent. The ends of the cover 90 disposed on anopposite surface of the stent 70 to the intermediate section of thecover 90, and between the bar member 76 and the turns 78 of the firstand second wall sections 83/84, is thus attached to the stent withoutfolding the ends of the cover around the ends of the stent from onesurface of the stent to the opposite surface of the stent. Consequently,the covered stent of the invention has a low profile, and improvedtrackability by reducing the tendency of the cover to get caught orengaged in tight spaces within the arterial lumen during advancement ofthe covered stent.

[0060] The first and second wall sections 83/84 are sufficientlyflexible to allow for bending up above the outer surface of theintermediate wall sections 85, or down below the inner surface of theintermediate wall sections 85, to facilitate placing the ends 91/92 ofthe cover 90 between the first and second wall sections 83/84 and thebar members 76 connected thereto. The wall sections 74 are preferablyformed of metal such as stainless steel.

[0061] In one embodiment, the cover 90 has a length substantially equalto the length of the stent 70. Substantially equal to should beunderstood to include a cover 90 with a length equal to, or not morethan about 5% less than, or not more than about 5% greater than thelength of the stent. In alternative embodiments, the cover has a lengthless than the length of the stent so that the stent is partially covered(not shown). In one embodiment having a partially covered stent, thecover is on the intermediate wall sections 85, and the ends of the stentare not covered. Thus, the cover is disposed over at least oneintermediate wall section 76 and under at least a second intermediatewall section 85, so that the cover is disposed between an intermediatewall section 85 and the bar member(s) 76 which connect the intermediatewall section 85 to an adjacent intermediate wall section 85. Thepartially covered stent having the cover on a middle section of thestent is particularly preferred for use applications such as TransJugular Intra-hepatic Portal Shunts (TIPS). In another embodiment havinga partially covered stent, the cover comprises two separate members oneither end of the stent with one or more intermediate sections of thestent not covered, or a single cover on one end of the stent with theremaining sections of the stent uncovered, the cover having an enddisposed between the first and/or the second wall section 83/84 and thebar member(s) 76 connected thereto, in accordance with the invention asdiscussed above. The partially covered stent having the cover on an endsection of the stent is particularly preferred for use at the site of abranch lumen, so that an uncovered middle section of the stent isprovided which does not occlude the branch lumen.

[0062] In the embodiment illustrated in FIG. 18, the ends 91/92 of thecover 90 do not extend beyond the ends 72/73 of the stent 70. In theembodiment illustrated in FIGS. 18 and 19, the first and second ends91/92 of the cover 90 are in contact with the concave surfaces 81 whichface toward the intermediate wall sections 85. Alternatively, the cover90 may have a shorter length with the first and second ends 91/92 of thecover in contact with sections of the turns 78 of the first and secondwall sections 83/84, respectively, which are closer to the intermediatewall sections 85. In a presently preferred embodiment, the cover 90 isfirst formed into a cylinder, as by sewing the edges of the sheet ofmaterial used to form the cover together, and then placed around thestent with the ends of the cover under the first and second wallsections 83/84. The edges of the cover are preferably facing andabutting one another to provide a low profile configuration, however, inalternative embodiments they may be in an overlapping relationship toone another.

[0063] In an alternative embodiment, one or both ends 91/92 of the covermay extend beyond the ends 72/73 of the stent. In the embodimentillustrated in FIG. 21, the cover has a slit 96 in the first end 91 ofthe cover 90, which allows the first end 91 of the cover 90 to extendbeyond the first end 72 of the stent. The end of the first wall section83 of the stent, at the location at which the bar member 76 is attachedthereto, is within the slit so that the connection between the firstwall section 83 and the bar member 76 does not block the end of thecover from extending beyond the end of the stent. After the cover 90 isin place on the stent with the end of the cover extending beyond thestent end, the cut edges of the cover defining the slit 96 arereconnected together, as for example by suturing as illustrated in FIG.21, or with other connecting methods such as staples or bonding withadhesive or fusing. In the embodiment having the end of the coverextending beyond the end of the stent, the end of the cover can beclosed off before the covered stent assembly is introduced into thepatient's body lumen. After the covered stent is implanted in the bodylumen, the closed end of the cover thus closes or occludes the bodylumen to prevent or inhibit fluid flow therein. FIG. 22 illustrates thecovered stent assembly of FIG. 21, after the edges of the open end 91 ofthe cover 90 have been brought together and secured to close off the endof the cover. The end of the cover is closed off using sutures, as bestillustrated in FIG. 23 which illustrates a transverse view of the end ofthe covered stent shown in FIG. 22, taken along line 23-23. However, theend of the cover can be closed off using a variety of suitable methodsincluding stapling, and bonding with adhesives or fusing.

[0064] In the embodiment illustrated in FIG. 17, stent 70 has eyeletmembers 75 at either end of the wall sections 74. The eyelet members 75are open loops defined at least in part by the concave surface 81 of theturn 78 of the wall section 74. However, a variety of suitable eyeletmembers may be provided including the closed loop eyelet members whichare on the tubular body or on support members or bar members extendingbetween longitudinally adjacent wall sections 74 as discussed above inrelation to the embodiments of FIGS. 11, 12 and 14. The eyelet members75 at the center of a turn 78 have parallel sides 95 and a smaller innerdiameter than sections of the turn adjacent to the eyelet member 75. Theturns 78 have sections which taper to the smaller diameter eyeletmembers 75. In a presently preferred embodiment, sutures (not shown) areprovided along the length and around the circumference of the stent 70through eyelet members 75, connecting the cover 90 thereto. However, inalternative embodiments, sutures are provided intermittently or atselected locations on the stent 70.

[0065] In a presently preferred embodiment of the stent assembly of FIG.18, the cover 90 is heterologous tissue such as pericardium, leaflet,veins, arteries, and the like. However, synthetic materials includingfluoropolymers such as PTFE and polyesters such as Dacron can also beused. Preferably the cover 90 is sufficiently compressible to allow thecover 90 to be compressed between the first and second wall sections83/84 and the bar members 76 connected thereto. The cover preferably hasa thickness of about 0.001 mm to about 2 mm, and most preferably about0.10 mm to about 0.15 mm. The tissue may be thinned by cutting layers oftissue away, to provide a sufficiently thin cover 90.

[0066]FIGS. 17-23 illustrate all the wall sections 74 of the stenthaving a configuration with turns 78 connected by bar members 76 tolongitudinally adjacent wall sections 74. However, it should beunderstood that the intermediate wall section(s) 85 may have a varietyof configurations including comprising one continuous member extendingaround the stent circumference. Thus, in one embodiment only the firstand second wall sections 83/84 at the ends of the stent 70 comprises theturns 78 connected by bar members 76 to the adjacent wall section asillustrated, so that the stent is configured to allow the cover to bedisposed under the first and second wall sections 83/84 at the ends ofthe stent 70, and over the intermediate wall section(s) 85.Additionally, while discussed and shown in terms of rounded wall sectionturns 78 having concave and convex surfaces 81/82, it should beunderstood that the turns 78 of the wall section 74 may comprises angledsurfaces having a V-shaped configuration, with internal and externalsurfaces at a central section of the turn which are more sharply angledthan the more gradually curved surfaces 81/82 illustrated in FIG. 17.

[0067] Although primarily described with respect to preventingrestenosis in angioplasty patients, the covered stents of this inventionmay be used in a number of coronary artery, peripheral artery andnon-vascular applications. For example, coronary artery applicationsinclude use in ectatic arteries and ectatic arteries containing anobstructive lesion, aneurismatic arteries, saphenous vein grafts andnative arteries, coronary perforation, coronary fistula, and ostialcoronary lesions. Peripheral artery applications include aorticabdominal aneurysm and other aneurismatic peripheral arteries,transjugular intrahepatic portal shunt, percutaneous transluminalangioplasty, fistula closing and neuro interventions (such as aneurysmsand arterial-venous malformations), small vessel intraluminal grafting,and ostial renal artery lesions. Finally, the covered stents of thisinvention may be used in urological, gastroenterological, respiratory,neurological, and other non-vascular applications. For example,urological field applications include urethral stenting for stenosis dueto tumors, fibrous tissue and perforation. Gastroenterological fieldapplications include fistula closing, reconstruction such as esophagusreconstruction, and esophageal bleeding. Respiratory field applicationsinclude tracheal and bronchial obstructions, and neurological fieldapplications include carotid angioplasty.

[0068] A general description of the device of the present invention aswell as a preferred embodiment of the present invention has been setforth above. One skilled in the art will recognize and be able topractice many changes in many aspects of the device described above,including variations that fall within the teachings of this invention.For example, although the cover is illustrated on the outer surface ofthe stent, a cover may be secured to an inner surface of the stent usingthe cover connectors of the invention. Additionally, although the coveris illustrated primarily in terms of a sheet of material forming acylinder about the stent, the cover connectors may be used to attach avariety of covers to the stent such as ribbons of material wrapped inwhole or in part about the stent. The stent assembly may be used inbranched body lumens, and positioned to block one or more of the branchlumens or reconstruction of bifurcations by a specially tailoredbifurcated cover stent.

1-23. (canceled)
 24. An expandable tubular stent body having a pluralityof interconnected cylindrical wall sections, comprising: a) a firstcylindrical wall section at a first end of the tubular body which has afirst margin and a second margin and a circumferentially undulatedstructure with undulation extremities at the first and second margins ofthe first cylindrical wall section; b) a second cylindrical wall sectionat a second end of the tubular body; c) an intermediate cylindrical wallsection which is disposed adjacent to the first cylindrical wallsection, which has a first margin and a second margin with the firstmargin adjacent to the second margin of the first cylindrical wallsection and a circumferentially undulated structure with undulationextremities at the first and second margins of the intermediatecylindrical wall section; d) at least one interconnecting memberextending between an undulation extremity at the first margin of thefirst cylindrical wall section and an undulation extremity at a marginof the adjacent intermediate cylindrical wall section, and e) a coverconnector configured to secure a cover to an exterior portion of thetubular stent body.
 25. The expandable tubular stent body of claim 24wherein the undulated structure of the first cylindrical wall sectionand the undulated structure of the adjacent intermediate cylindricalwall section are in phase.
 26. The expandable tubular stent body ofclaim 25 wherein the interconnecting member extends between anundulation extremity at the first margin of the first cylindrical wallsection and an undulation extremity at the first margin of the adjacentintermediate cylindrical wall section
 27. The expandable tubular stentbody of claim 24 wherein the undulated structure of the firstcylindrical wall section and the undulated structure of the adjacentintermediate cylindrical wall section are out of phase.
 28. Theexpandable tubular stent body of claim 27 wherein the interconnectingmember extends between an undulation extremity at the first margin ofthe first cylindrical wall section and an undulation extremity at thesecond margin of the adjacent intermediate cylindrical wall section. 29.The expandable tubular stent body of claim 24 wherein at least oneinterconnecting member has a cover connector.
 30. The expandable tubularstent body of claim 29 wherein the cover connector has a penetratingelement to secure a jacket thereto.
 31. The expandable tubular stentbody of claim 29 wherein the cover connector has a eyelet to facilitatesecuring a stent cover thereto by a suitable strand.
 32. The expandabletubular stent body of claim 24 wherein at least one of theinterconnecting members is an elongated bar.
 33. An intravascular stent,comprising: a) an expandable tubular stent body which has a plurality ofinterconnected cylindrical wall sections including a first cylindricalwall section, a second cylindrical wall section, and at least oneintermediate cylindrical wall section between the first and secondcylindrical wall sections, and at least one interconnecting memberextending between the first cylindrical wall section and alongitudinally adjacent intermediate cylindrical wall section; and b) astent cover connector which is configured to secure a stent cover to thetubular stent body.
 34. The intravascular stent of claim 33 wherein thecover connector has a cover penetrating element to secure the stentcover.
 35. The intravascular stent of claim 33 wherein the coverconnector has a pair of cover penetrating elements to secure the stentcover.
 36. The intravascular stent of claim 33 wherein the penetratingelements of the cover connector are configured to penetrate through astent cover and be folded over an exterior portion of the stent cover tosecure the stent cover to the stent body.
 37. The intravascular stent ofclaim 33 wherein the interconnecting member has the stent coverconnector.
 38. The intravascular stent of claim 37 wherein the stentcover connector of the interconnecting member has a penetrating elementto secure the stent cover.
 39. The intravascular stent of claim 33wherein the cover connector of the interconnecting member has at leastone eyelet to facilitate securing a stent cover thereto by a suitablestrand.
 40. The stent assembly of claim 33 wherein the first cylindricalwall section has a circumferentially undulated structure.
 41. The stentassembly of claim 40 wherein the circumferentially undulated structureof the first cylindrical wall section has a first circumferential marginand a second circumferential margin with undulation extremities at thefirst and second margins.
 42. The stent assembly of claim 41 wherein theintermediate cylindrical wall section adjacent to the first cylindricalwall section has a circumferentially undulated structure.
 43. The stentassembly of claim 42 wherein the undulated structure of the firstcylindrical wall section and the undulated structure of the adjacentintermediate cylindrical wall section are in phase.
 44. The stentassembly of claim 42 wherein the undulated structure of the firstcylindrical wall section and the undulated structure of the adjacentintermediate cylindrical wall section are out of phase.
 45. The stentassembly of claim 43 wherein the interconnecting member extends betweenan undulation extremity at the first margin of the first cylindricalwall section and an undulation extremity at the first margin of theadjacent intermediate cylindrical wall section
 46. The stent assembly ofclaim 33 wherein at least one of the interconnecting members is anelongated bar.